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  • 1
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    European Aquaculture Society
    In:  In: Lessons from the past to optimise the future. , ed. by Howell, B. and Flos, R. EAS special publication, 35 . European Aquaculture Society, Oostende, Belgium, pp. 465-466.
    Publikationsdatum: 2014-03-10
    Materialart: Book chapter , PeerReviewed
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  • 2
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Science, Ltd
    Plant, cell & environment 24 (2001), S. 0 
    ISSN: 1365-3040
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Field-collected specimens of three species of Laminaria and three species of subtidal red algae (Delesseria sanguinea, Plocamium cartilagineum and Phyllophora pseudoceranoides) were exposed to natural summer sunlight on Helgoland (southern North Sea) for up to 4 h at 15 °C. Dark-adapted variable fluorescence (Fv : Fm) was measured immediately after these treatments, and following 6, 24 and 48 h of recovery in moderate irradiances of white light. The response of plants to the full spectrum of natural sunlight was compared with that to PAR alone, UV-A + visible, UV-A + UV-B, or UV-A alone. The Fv : Fm values of all species were reduced to minimal values after 4 h in all of these treatments, but those of the more resistant species (Laminaria spp. and P. pseudoceranoides) were higher after shorter exposures to UV radiation alone than to PAR with or without UV. The recovery of Fv : Fm in all species was also more rapid in the two treatments that contained UV radiation alone than in those that included PAR. These results suggest that it is the high irradiances of PAR in natural sunlight which are responsible for the photoinhibition of photosynthesis of subtidal seaweeds and that the current ambient irradiances of UV radiation (either UV-B or UV-A) in northern temperate latitudes would not contribute significantly to this photoinhibition.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    [s.l.] : Nature Publishing Group
    Nature 279 (1979), S. 430-431 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] Fig. 1 Capillary gas- Chromatographie separation of extracts from female gametophytes of Laminaria digitata. a, normal alkanes ranging from heptane to nonadecane separated in identical conditions; b, 3-d-old suspension without eggs, extracted for 22.5 h ; c, suspension containing 8.7 x 10 eggs, ...
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    [s.l.] : Nature Publishing Group
    Nature 199 (1963), S. 303-304 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] Table 1. EFFECT ON INTRA-UTERINE DEATH IN OFFSPRING AFTER INJECTION OF STRONTIUM-90, 18 µC. /ANIMAL, IN MALES MATED 11-15 WEEKS AFTER INJECTION (SPERMATOGONIA) Treatment Dead Implants % dead 90Sr 260 3,242 8.02 NaCl 212 3, 339 6.35 90Sr versus sodium chloride X2 = 6.89; D.F. ...
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    [s.l.] : Nature Publishing Group
    Nature 178 (1956), S. 1123-1124 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] From experiments by Baker and Von Halle6 with fast neutrons it is known that the rates of dominant lethals were the same in sperm from the first and the second day. This result is difficult to explain on the hypothesis of a difference in sensitivity between sperm of the first two days. Hence it ...
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    [s.l.] : Nature Publishing Group
    Nature 197 (1963), S. 304-305 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] In order to distinguish between these two processes, which are not mutually exclusive, we also examined the effects of injections with caesium-137, which within the animal emits most of its radiation energy through (3-radiation, as does strontium-90. If at first the time that the isotopes are in ...
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Helgoland marine research 27 (1975), S. 108-114 
    ISSN: 1438-3888
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung 1. Zwei morphologisch verschiedene Formen der BraunalgeLaminaria saccharina (Helgoländer Form mit glatten Phylloiden, Form von der Isle of Man mit Phylloidhöckern) wurden gekreuzt. 2. Die von der Isle of Man stammende Form sowie die reziproken Bastarde entwickelten auch im Helgoländer Sublitoral Phylloidhöcker. 3. Die englische Form hatte breitere Phylloide als die Helgoländer Form und verfiel ab Juli, als die Wassertemperatur bei Helgoland 14° C überschritt. 4. Alle Versuchspflanzen wurden nach viermonatigem Aufenthalt wieder aus dem Meer entnommen. Eine Kontamination der Helgoländer Unterwasserflora mit der nichtheimischen Form kann ausgeschlossen werden.
    Notizen: Abstract The brown algaLaminaria saccharina growing at Helgoland (North Sea) has smooth blades, whereas the blades of the same species occurring at the Isle of Man are covered with deep bullations. Gametophytes of both morphological types were grown in the laboratory and the resulting sporophytes of each type as well as hybrids were planted out in the sublittoral zone of Helgoland for four months. The Isle of Man type and the hybrids both formed bullations. The Isle of Man type differed further from the Helgoland type in that it had broader blades and did not tolerate the water temperatures above 14° C which prevail near Helgoland in summer. All experimental plants were removed from the sea before the blades became sporogenous.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Helgoland marine research 29 (1977), S. 311-314 
    ISSN: 1438-3888
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Alaria esculenta (L.) Grev. sporophytes, raised in culture and originating from the North of Iceland were immersed in the sea near Helgoland (North Sea) for the period from February to August. Notable growth of the thalli was found between February and May, when the water temperature was similar to that of their original habitat in Iceland. Less conspicuous growth but development of sporophylls took place between May and July. The temperature rose to 16.8° C during the first half of July and remained on the same level during August, when the plants deteriorated. The present experiments yield additional evidence that the regional distribution ofA. esculenta is temperature controlled.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Helgoland marine research 34 (1980), S. 15-29 
    ISSN: 1438-3888
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Three eulittoral algae(Ulva lactuca, Porphyra umbilicalis, Chondrus crispus) and one sublittoral alga(Laminaria saccharina) from Helgoland (North Sea) were cultivated in a flow-through system at different temperatures, irradiances and daylengths. In regard to temperature there was a broad optimum at 10–15° C, except inP. umbilicalis, which grew fastest at 10 °C. A growth peak at this temperature was also found in four of 17 other North Sea macroalgae, for which the growth/temperature response was studied, whereas 13 of these species exhibited a growth optimum at 15 °C, or a broad optimum at 10–15 °C. Growth was light-saturated inU. lactuca, L. saccharina andC. crispus at photon flux densities above 70 µE m−2s−1, but inP. umbilicalis above 30 µE m−2s−1. Growth rate did not decrease notably in the eulittoral species after one week in relatively strong light (250 µE m−2s−1), but by about 50 % in the case of the sublittoralL. saccharina, as compared with growth under weak light conditions (30 µE m−2s−1). In contrast, chlorophyll content decreased in the sublittoral as well as in the eulittoral species, and the greatest change in pigment content occurred in the range 30–70 µE m−2s−1. Growth rate increased continuously up to photoperiods of 24 h light per day inL. saccharina andC. crispus, whereas daylength saturation occurred at photoperiods of more than 16 h light per day inU. lactuca andP. umbilicalis.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Helgoland marine research 41 (1987), S. 283-295 
    ISSN: 1438-3888
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Plants ofGigartina teedii from the mediterranean isolated into laboratory culture showedPolysiphonia-type life histories with consistent formation of dioecious gametangial plants, as previously reported for Atlantic isolates. Male and female plants from the Atlantic and Mediterranean were almost completely compatible in terms of cystocarp formation on female plants, and carpospores from positive crosses always formed plants that released viable tetraspores. Sex-linked inheritance of branching pattern was found in all strains, but showed varying degrees of expression. Female plants were more branched than male plants and it is suggested that this may be an adaptation for spermatial capture.G. teedii plants showed differences in morphology in culture that are considered to be genetically-based. Preliminary studies of tip elongation showed that Mediterranean strains may have up to three times the elongation rates of Atlantic strains at 15°C, $$\bar 8$$ . Such genetic variation in fully-interbreeding strains suggests that populations of this species in the Atlantic and Mediterranean are genecodemic. All strains showed an upper temperature tolerance of 31°C when tested at 1°C intervals from 29—34°C. An upper temperature tolerance of 31–32°C was found for the related speciesG. intermedia from Korea and Japan, butG. johnstonii from the Gulf of California showed an upper tolerance of 32–33°C.
    Materialart: Digitale Medien
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